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We characterize when a C*-cover admits a C*-dynamical extension of dynamics on an operator algebra in terms of the boundary ideal structure for the operator algebra in its maximal representation and show that the C*-covers that admit such…

Operator Algebras · Mathematics 2024-03-25 Mitch Hamidi

We continue our study of tensor products in the operator system category. We define operator system quotients and exactness in this setting and refine the notion of nuclearity by studying operator systems that preserve various pairs of…

Operator Algebras · Mathematics 2010-08-19 Ali S. Kavruk , Vern I. Paulsen , Ivan G. Todorov , Mark Tomforde

We give an order-theoretic characterization of the essential image of the forgetful functor from the category of real/complex unital C*-algebras to the category of real/complex unital operator systems. It is based on the characterization of…

Operator Algebras · Mathematics 2026-04-24 Samuel Tiersma

Let $\gamma = (\gamma_1,...,\gamma_N)$, $N \geq 2$, be a system of proper contractions on a complete metric space. Then there exists a unique self-similar non-empty compact subset $K$. We consider the union ${\mathcal G} = \cup_{i=1}^N…

Operator Algebras · Mathematics 2007-05-23 Tsuyoshi Kajiwara , Yasuo Watatani

A notion of super operator system is defined which generalizes the usual notion of operator systems to include certain unital involutive operator spaces which cannot be represented completely isometric as a concrete operator system on some…

Operator Algebras · Mathematics 2013-08-05 Ulrich Haag

We study two classes of operator algebras associated with a unital subsemigroup $P$ of a discrete group $G$: one related to universal structures, and one related to co-universal structures. First we provide connections between universal…

Operator Algebras · Mathematics 2022-03-09 Evgenios T. A. Kakariadis , Elias G. Katsoulis , Marcelo Laca , Xin Li

Starting with a $W^{*}$-algebra $M$ we use the inverse system obtained by cutting down $M$ by its (central) projections to define an inverse limit of $W^{*}$-algebras, and show that how this pro-$W^{*}$-algebra encodes the local structure…

Operator Algebras · Mathematics 2007-05-23 Massoud Amini

We investigate some subtle and interesting phenomena in the duality theory of operator spaces and operator algebras. In particular, we give several applications of operator space theory, based on the surprising fact that certain maps are…

Operator Algebras · Mathematics 2007-05-23 David P. Blecher , Bojan Magajna

We transfer the theory of slack operators and sums-of-squares-criteria for lifts from convex cones to operator systems. These allow to study the following question, among others: Given an abstract operator system, is its enveloping…

Operator Algebras · Mathematics 2025-08-22 Markus Dannemüller , Tim Netzer

A vector subspace $\cls$ of $\IM_n(\IC)$ is called unital operator system if $x \in \cls$ if and only if $x^* \in \cls$ and the identity operator $I_n \in \cls$, where $n$ is any fixed positive integer. Let $C^*(\cls)$ be the $C^*$…

Functional Analysis · Mathematics 2023-08-03 Anilesh Mohari

We give several applications of a recent theorem of the second author, which solved a conjecture of the first author with Hay and Neal, concerning contractive approximate identities; and another of Hay from the theory of noncommutative peak…

Operator Algebras · Mathematics 2011-02-22 David P. Blecher , Charles John Read

We say that a contractive Hilbert space operator is universal if there is a natural surjection from its generated C*-algebra to the C*-algebra generated by any other contraction. A universal contraction may be irreducible or a direct sum of…

Operator Algebras · Mathematics 2019-05-06 Kristin Courtney , David Sherman

This paper extends the Kadison duality between compact convex sets and function systems to the setting of partial convexity. A partially convex set is a set that is convex in a designated set of convex variables when the others are held…

Functional Analysis · Mathematics 2026-05-06 Tea Štrekelj

In this article we survey some of the recent goings-on in the classification programme of C$^*$-algebras, following the interesting link found between the Cuntz semigroup and the classical Elliott invariant and the fact that the Elliott…

Operator Algebras · Mathematics 2009-02-20 Pere Ara , Francesc Perera , Andrew S. Toms

We continue the study of multidimensional operator multipliers initiated in [arXiv:math/0701645]. We introduce the notion of the symbol of an operator multiplier. We characterise completely compact operator multipliers in terms of their…

Operator Algebras · Mathematics 2015-02-06 K. Juschenko , R. H. Levene , I. G. Todorov , L. Turowska

We introduce an operator system, universal for the probabilistic models of a contextuality scenario, and identify its maximal C*-cover via the right C*-algebra of a canonical ternary ring of operators, arising from a hypergraph version of…

Operator Algebras · Mathematics 2025-09-19 Michalis Anoussis , Alexandros Chatzinikolaou , Ivan G. Todorov

We study some topological spaces that can be considered as hyperspaces associated to noncommutative spaces. More precisely, for a NC compact space associated to a unital C*-algebra, we consider the set of closed projections of the second…

Operator Algebras · Mathematics 2017-01-09 Maysam Maysami Sadr

We continue our study of the general theory of possibly nonselfadjoint algebras of operators on a Hilbert space, and modules over such algebras, developing a little more technology to connect `nonselfadjoint operator algebra' with the…

Operator Algebras · Mathematics 2007-05-23 David P. Blecher

The notion of qausi-product actions of a compact group on a C$^*$-algebra was introduced by Bratteli et al. in their attempt to seek an equivariant analogue of Glimm's characterization of non-type I C$^*$-algebras. We show that a faithful…

Operator Algebras · Mathematics 2024-05-07 Masaki Izumi

We introduce quotient maps in the category of operator systems and show that the maximal tensor product is projective with respect to them. Whereas, the maximal tensor product is not injective, which makes the $({\rm el},\max)-nuclearity…

Operator Algebras · Mathematics 2011-06-07 Kyung Hoon Han